The present invention relates to the general field of air discharge systems in a compressor of an aviation turbomachine.
During certain stages in the operation of an aviation turbomachine of the bypass type, it is known to divert a fraction of the air flowing in the primary channel of the turbomachine in order to take the air into the secondary channel (coaxial with the primary channel) so as to increase temporarily the aerodynamic stability of the flow of air through the compressor. To this end, the compressor of the turbomachine includes in its outer shroud air takeoff orifices that open out into the secondary channel.
Air discharge valves serve to control the flow rate of air that is taken from the compressor and injected into the secondary channel. Different types of air discharge valve are known. For example, there are butterfly valves or poppet valves. These discharge valves are generally driven independently via individual controls (e.g. one hydraulic actuator per butterfly valve or a pneumatic system having one solenoid valve per poppet valve).
Such air discharge valves present numerous drawbacks. In particular, the use of hydraulic or pneumatic control members for activating discharge valves presents the drawback of requiring pipework for conveying the control fluid, and also solenoid valves, filters, etc. Unfortunately, such equipment presents a high cost, and non-negligible weight and size. Furthermore, poppet or butterfly type discharge valves are not accurate, such that it is generally difficult to have good control over the air flow rate that is taken off. There therefore exists a risk that too much air will often be taken from the compressor, with all the drawbacks to which that leads (risk of breaking blades, influence on cabin pressure, etc).